1. External Processes Erosion Weathering

2. Table of Contents DateTitleLesson # 8/275 Themes of Geography2 8/28The 5 A’s3 8/31Geographer’s Tools4 9/1Internal Forces5 9/3External Forces6 1. Draw a line underneath wherever you left off yesterday. 2. Write the title “External Forces”

3. Weathering - forces that are changing rocks, land, and objects over time, even day to day. 2 types: Mechanical Weathering and Chemical Weathering COPY WHAT’S IN THE BOX

4. Mechanical weathering – a force breaks a rock into smaller pieces by forcing them apart. - Example: Breaking large rocks into smaller ones COPY WHAT’S IN THE BOX

5. Causes of Mechanical Weathering 1. Root wedging – roots break up rocks 2. Frost Wedging - ice get into rocks 3. Thermal expansion – heat causes rocks to expand and break COPY WHAT’S IN THE BOX

6. Effects of Mechanical Weathering

7. Conclusion How is mechanical weathering like a hammer? Directions: Copy the sentence above and write one complete sentence responding to it in your notebook.

8. Chemical Weathering Chemical weathering - when something "eats away" at a rock instead of breaking it apart. Requires a chemical change in the rocks COPY WHAT’S IN THE BOX

9. Causes of Chemical Weathering 1. Acid Rain Directions: - Copy the headline and each cause -Under where you wrote Acid Rain, briefly explain each step of the Acid Rain process in your notebook.

10. Regions Sensitive to Acid Rain Orso University Challenge Question: Why do Houston, Chicago, and Los Angeles have such low levels of acid rain?

11. Causes of Chemical Weathering 2. Water – creates a chemical reaction in certain objects 3. Chemicals – resulting from pollution or internal processes Foaming pollution on rocks.

12. Effects of Chemical Weathering At PH1, this New Zealand lake is pure hydrochloric acid Naked trees Rust

13. Analysis - Create a weathering wonderland. -Sketch a landscape that includes examples of weathering resulting from each of the 6 causes. (3 mechanical, 3 chemical) -Label each cause

14. Rocks that have split apart due to thermal expansion. Directions/Requirements - Need 6 pictures (3 mechanical weathering and 3 chemical weathering) - Need a caption explaining each cause - Need a title

15. Weathering Wonderland Conclusion You are the mayor of a new city called Weathering Wonderland. 1. How does weathering harm your city? 2. How can you be proactive in addressing the problems caused by weathering? - List and EXPLAIN three steps you will take to ensure that problems from weathering are minimized.

16. Closure 1. Answer the Question of the Day.